Characteristics of putrescine uptake in isolated rat enterocytes.

Polyamines are necessary for the growth of eukaryotic cells and are supplied either by new synthesis or cellular uptake. To our knowledge, no information is available on polyamine uptake by gastrointestinal cells. In the current study, isolated villous enterocytes from the rat accumulated putrescine to an eightfold concentration gradient.

Cyclic AMP in gastric juice does not reflect histamine H2 receptor activity in Heidenhain pouch dog.

It is strongly believed that cAMP mediates histamine H2 receptor activity, but does not mediate gastrin and acetylcholine stimulation of gastric acid secretion. Therefore, cAMP production could be a marker of H2 receptor activity. Whether endogenous histamine mediates gastrin and/or acetylcholine stimulation, at least partially, remains to be elucidated.

The role of carbonic anhydrase in gastric mucosal protection with special reference to H+ back diffusion and concomitant metabolic acidosis induced by acetazolamide.

It is suggested that carbonic anhydrase is implicated not only in gastric acid secretion, but in mucosal protection. It was reported that acetazolamide induced gastric mucosal lesions. But acetazolamide also caused concomitant metabolic acidosis by inhibiting H+ secretion from renal tubules.

Evaluation of the new giant-biopsy forceps in the diagnosis of mucosal and submucosal gastric lesions.

In order to improve the diagnosis of gastric disorders on the basis of biopsy material, we devised larger biopsy forceps (5 mm X 2.5 mm in inside dimensions) which fit into the newer fibergastroscope, GIF-1T (Olympus). Samples from 116 cases yielded 276 specimens; 179 specimens (64.

In vitro regeneration of resting lymphocytes from stimulated lymphocytes and its inhibition by insulin.

Concanavalin A- (Con A) stimulated mouse lymphocytes were separated from unstimulated cell populations by a bovine serum albumin (BSA) density gradient centrifugation 2 days after the stimulation. The stimulated cells divided, but did not initiate a new round of DNA replication when cultured further in the absence of Con A. The divided cells became similar in various properties to unstimulated lymphocytes during a prolonged incubation, suggesting that they entered the resting state.

Fluorometric investigation of the local conformation of 16S rRNA in the regions of the 3'- and 5'-ends.

The conformational changes of ribonucleic acid induced by heat treatment were studied by measurements of fluorescence polarization, circular dichroism, and ultraviolet absorption. The fluorescence polarization of proflavine covalently bound to the 3'-end of 16S ribosomal RNA of Escherichia coli and that of ethenoadenosine conjugated to the 5'-end of the RNA indicated that a conformational difference existed between heat-treated and untreated samples of the RNA in the regions near the 3'- and 5'-ends. Comparison of the fluorescence polarization data with other optical measurements indicated that the local conformation around the 3'- and 5'-ends of the RNA was converted to a more rigid and stable form by the heat treatment, while the gross conformation did not appear to change.